JP7067433B2 - Motor vehicle drive unit - Google Patents

Description

The present specification relates to an electric vehicle drive unit including a power control device and a vehicle drive device.

Techniques have been developed to form an electric vehicle drive unit by fixing the power control device housed in the case and the vehicle drive device housed in the case. In the unit, it is necessary to connect the power control device and the vehicle drive device with a conductive member, and an opening through which the conductive member passes is formed in both the case of the power control device and the case of the vehicle drive device. back. In order to protect the conductive member from the outside world and airtightly seal both openings, a sealing member may be provided around the conductive member. The seal member airtightly seals both the opening on the power control device side and the opening on the vehicle drive device side. Further, the conductive member penetrates the inside of the seal member and passes through the opening on the power control device side and the opening on the vehicle drive device side.

A large current whose magnitude changes sharply flows through the power control device, the conductive member, and the vehicle drive device, and radiates electromagnetic noise to the surroundings. Electronic devices affected by the electromagnetic noise may be placed in the vicinity of the electric vehicle drive unit, and countermeasures against the electromagnetic noise are required.

Regarding the power control device and the vehicle drive device, it is possible to take measures against electromagnetic noise by forming each case with a conductive member and grounding the case. Regarding the conductive member that connects the two, electromagnetic noise can be countered by forming a sealing member that surrounds the conductive member with the conductive member, but both the opening on the power control device side and the opening on the vehicle drive device side are open. It is difficult to form a sealing member that needs to be airtightly sealed with a conductive member, and measures against electromagnetic noise radiated from the conductive member located between the case of the power control device and the case of the vehicle drive device are taken. is required.

The power control device is typically an inverter that converts the direct current power of the power source into alternating current. The power controller may also include a boost converter. Further, the vehicle drive device is typically a traveling motor. The electric vehicle in the present specification includes not only an electric vehicle but also a hybrid vehicle and a fuel cell vehicle.

Japanese Unexamined Patent Publication No. 2015-205596

Patent Document 1 shows a technique for conducting a metal case and a metal bracket by a braided wire when the metal case and the metal bracket of the power control device are fixed via an insulating anti-vibration bush. This technique is a technique for grounding a metal case of a power control device, and does not take measures against electromagnetic noise radiated from a conductive member located between the case of the power control device and the case of the vehicle drive device.
This specification discloses a technique for dealing with electromagnetic noise radiated from a conductive member located between a case of a power control device and a case of a vehicle drive device.

In the electric vehicle drive unit to which this technique is applied, an intermediate member is interposed between the power control device and the vehicle drive device, and a conductive shielding plate is arranged. The power control device is housed in a conductive first case with a first opening, and the vehicle drive device is housed in a conductive second case with a second opening. The intermediate member includes a non-conductive sealing member that airtightly seals the first opening and the second opening, and a conductive member that penetrates the inside of the sealing member and passes through the first opening and the second opening. There is. A conductive shielding plate is arranged on the outside of the non-conductive sealing member. The conductive shielding plate is connected to both the first case and the second case.

In the above electric vehicle drive unit, a conductive shield plate is arranged on the outside of the non-conductive seal member, and the conductive shield plate is connected to both the case of the power control device and the case of the vehicle drive device. .. According to this, when a fluctuating current flows in the conductive member and a magnetic field is generated around the conductive member, an induced current flows in a conductive shielding plate arranged outside the conductive member, and the induced current causes a magnetic field. Occur. The magnetic field in which the induced current is generated is in the opposite direction to the magnetic field caused by the fluctuating current flowing through the conductive member, and cancels the magnetic field caused by the fluctuating current passing through the conductive member. As a result, the strength of the electromagnetic noise propagating beyond the conductive shielding plate is reduced, and the inductance of the conductive member is reduced. As a result, the electromagnetic noise radiated from the conductive member located between the case of the power control device and the case of the vehicle drive device is suppressed from propagating beyond the conductive shielding plate, and it is necessary to protect it from the electromagnetic noise. Can protect certain electronic devices from electromagnetic noise.

The fact that the conductive shielding plate is arranged on the outside of the non-conductive seal member includes both the case where it goes around the outer circumference of the seal member and the case where it is arranged on a part of the outer circumference. When the placement position of the electronic device that needs to be protected from electromagnetic noise is limited, by arranging a conductive shielding plate in a part, the electronic device can be protected from the electromagnetic noise by the conductive shielding plate. ..
Further, the case where the conductive member passes through the opening includes both the case where the conductive member passes in a state of being covered with the seal member and the case where the conductive member passes in a state of being exposed from the seal member. The sealing member that seals the opening may penetrate into the opening or stay outside the opening.

Details and further improvements to the techniques disclosed herein will be described in the "Modes for Carrying Out the Invention" section below.

It is an upper perspective view which shows the component layout in the front compartment of the hybrid vehicle which mounts the electric vehicle drive unit of an Example. It is a side view of the electric vehicle drive unit of an Example. It is the upper perspective view which expanded the range of III in FIG. It is an upper perspective view which shows the assembly process (1) of the electric vehicle drive unit of an Example. It is an upper perspective view which shows the assembly process (2) of the electric vehicle drive unit of an Example. It is a partial cross-sectional view of the electric vehicle drive unit in VI-VI of FIG. It is a distribution map which shows the intensity of the electromagnetic noise before and after the service cover arrangement. It is a distribution map which shows the component direction of the magnetic field before and after the service cover arrangement.

The electric vehicle drive unit 10 of the embodiment will be described with reference to the drawings. FIG. 1 shows the arrangement of equipment in the front compartment 4 of the hybrid vehicle 2. In FIG. 1, the rear part of the hybrid vehicle 2 is omitted. As shown in FIG. 1, the front compartment 4 is adjacent to devices such as an electric vehicle drive unit 10, an engine 14, and an ECU 12. Other equipment is arranged in the front compartment 4, but the description thereof is omitted here. In FIG. 1, each device is schematically drawn.

The electric vehicle drive unit 10 is composed of a trans axle 6 and a PCU 8 (abbreviation of Power Control Unit) fixed on the trans axle 6. The transcycle 6 accommodates a motor 22 (see FIG. 2), a power distribution mechanism, a differential gear, and the like. The power distribution mechanism and the differential gear are not shown. The case of the trans-askle 6 is made, for example, by die-casting or machined aluminum. That is, the case of the trans axle 6 has conductivity. The detailed structure and function of the transcycle 6 will not be described.

Further, the PCU 8 houses the inverter 24 (see FIG. 4). The PCU 8 is a device that drives a traveling motor 22 (see FIG. 2). More specifically, the PCU 8 boosts the power of a high-voltage battery (not shown), converts it into alternating current, and supplies it to the motor 22. The case of PCU8 is made by die-casting or machined aluminum, for example. That is, the case of PCU8 has conductivity. The detailed structure and function of the PCU8 will not be described.

The details of the structure of the electric vehicle drive unit 10 will be described with reference to FIG. FIG. 2 is a side view of the electric vehicle drive unit 10 as viewed from the left side of the vehicle, that is, the positive side of the H axis. As described above, the PCU 8 is fixed on the trans axle 6. As shown in FIG. 2, the transcycle 6 and the PCU 8 are directly fixed. In other words, the transcycle 6 and the PCU 8 are in contact with each other. As mentioned above, the cases of the trans axle 6 and the PCU 8 are both made of aluminum. That is, both cases have conductivity. Although not shown, the transcycle 6 is electrically connected to the body of the hybrid vehicle 2. That is, the electric vehicle drive unit 10 is grounded to the body of the hybrid vehicle 2. The case of the trans axle 6 is closed by a cover from the positive side of the H axis. As shown in FIG. 2, the cover of the trans axle 6 is fixed from the positive side of the H axis by a plurality of bolts 18a.

Further, as shown in FIG. 2, a service cover 20 is provided at a connection portion between the PCU 8 and the trans axle 6 at the rear of the vehicle. Although detailed description will be described later, the service cover 20 is fixed to the PCU 8 by two bolts 18b and fixed to the trans axle 6 by one bolt 18b. Further, a terminal block 16 is provided between the trans axle 6 and the PCU 8.

FIG. 3 shows the details of the connection portion between the trans axle 6 and the PCU 8. FIG. 3 is an enlarged upper perspective view of the range of III in FIG. As shown in FIG. 3, the PCU 8 has a tubular portion extending toward the trans axle 6. Further, a terminal block 16 is provided between the cylinder portion and the trans axle 6. The terminal block 16 is fixed to the trans axle 6 by bolts 18c. The terminal block 16 is inserted into the tubular portion of the PCU 8. That is, the terminal block 16 is interposed between the PCU 8 and the trans axle 6. The details will be described later, but the terminal block 16 is made of resin. That is, the terminal block 16 does not have conductivity. In FIGS. 3 to 5, in order to help understanding, the portion showing the terminal block 16 is shown by hatching.

As shown in FIG. 3, the service cover 20 is fixed to both the PCU 8 and the trans axle 6 so as to cover the terminal block 16. Further, the service cover 20 is made of iron. That is, the service cover 20 has conductivity. In other words, the service cover 20 is arranged on the outside of the resin terminal block 16, and the service cover 20 is connected to both the case of the PCU 8 and the case of the trans axle 6.

Subsequently, the assembly process of the electric vehicle drive unit 10 of the embodiment will be described with reference to FIGS. 4 and 5. FIG. 4 shows a state before the terminal block 16 is inserted into the tubular portion of the PCU 8. As shown in FIG. 4, the terminal block 16 is fixed to the trans axle 6 by four bolts 18c so as to close the opening 6H of the trans axle 6. The bus bar 26 penetrates the inside of the terminal block 16 toward the PCU 8. The bus bar 26 connects the inverter 24 housed in the PCU 8 and the motor 22 (see FIG. 2) in three phases. Therefore, the three terminals of the bus bar 26 penetrate the inside of the terminal block 16. As shown by the arrow in FIG. 4, the PCU 8 is assembled to the trans axle 6 from above. At that time, the terminal block 16 airtightly seals the opening 8H of the PCU 8 from the inside. Further, the bus bar 26 passes through the opening 8H of the PCU 8.

FIG. 5 shows a state in which the PCU 8 is assembled to the trans axle 6. As described above, the three terminals of the bus bar 26 pass through the opening 8H of the PCU 8. As shown in FIG. 5, the three terminals of the bus bar 26 are fixed to the three terminals of the inverter 24 by bolts 18d. The tubular portion of the PCU 8 is provided with a service hole having a long hole shape extending in the front-rear direction of the vehicle. When assembling the electric vehicle drive unit 10, the terminal of the bus bar 26 and the terminal of the inverter 24 are connected by passing the bolt 18d through this service hole and fastening the bolt 18d. As a result, the bus bar 26 transmits three-phase alternating current from the inverter 24 to the motor 22 (see FIG. 2). After connecting the terminal of the bus bar 26 and the terminal of the inverter 24, the service cover 20 is attached so as to cover the service hole from the outside. By fixing the service cover 20 to both the case of the PCU 8 and the case of the trans axle 6 with three bolts 18b, the electric vehicle drive unit 10 of the embodiment is completed.

The electric vehicle drive unit disclosed in the present specification refers to a unit having a structure in which an intermediate member is interposed between the electric power control device and the vehicle drive device after the assembly is completed, and is intermediate with the vehicle drive device described above in advance. It is not limited to the one manufactured by connecting the power control device to the one to which the members are connected. It is also possible to manufacture by connecting a vehicle drive device to a device in which a power control device and an intermediate member are connected in advance.

The detailed structure of the terminal block 16 will be described with reference to FIG. FIG. 6 is a partial cross-sectional view of the electric vehicle drive unit 10 of VI-VI in FIG. As shown in FIG. 6, the opening 8H of the PCU 8 and the opening 6H of the trans axle 6 face each other. Further, there is a gap between the lower end of the PCU 8 and the upper surface of the trans axle 6. A terminal block 16 is provided so as to fill this gap. The terminal block 16 has a protrusion on the upper side and a flat plate portion on the lower side. The upper protrusion of the terminal block 16 has a packing 16a on its side surface. The packing 16a is fixed to the outer periphery of the upper protrusion of the terminal block 16. The upper protrusion of the terminal block 16 is inserted into the opening 8H of the PCU 8. The packing 16a is in contact with the inner surface of the opening 8H of the PCU in a certain relationship. That is, the packing 16a airtightly seals the opening 8H.

Further, the flat plate portion on the lower side of the terminal block 16 is arranged so as to cover the opening 6H of the transformer axle 6. A packing 16b is provided at the end of the lower surface of the flat plate portion of the terminal block 16. The packing 16b is in contact with the entire circumference of the peripheral edge of the opening 6H of the trans axle 6 in a constant relationship. That is, the packing 16b airtightly seals the opening 6H.

Here, as described above, the terminal block 16 is made of resin. The packings 16a and 16b are also made of rubber. That is, the terminal block 16 is non-conductive. The terminal block 16 airtightly seals the opening 8H of the PCU 8 and the opening 6H of the trans axle 6.

A method of fixing the terminal block 16 will be described with reference to FIG. As shown in FIG. 6, the terminal block 16 fixes the bus bar 26 at the lower central portion of the terminal block 16. The bus bar 26 penetrates the inside of the terminal block 16 in a state of being fixed to the terminal block 16. The bus bar 26 fixed to the terminal block 16 is inserted from above into the opening 6H of the transformer axle 6. At that time, the bus bar 26 passes through the opening 6H of the trans axle 6. After passing through the opening 6H, the bus bar 26 comes into contact with the motor terminal 22a. After that, the bus bar 26 and the motor terminal 22a are fixed by the bolt 18d. When fixing the bus bar 26 and the motor terminal 22a with the bolt 18d, the cover on the positive side of the H axis of the case of the trans axle 6 is not attached. Therefore, the bolt 18d can fix the bus bar 26 and the motor terminal 22a from the positive side of the H axis of the case of the trans axle 6. After that, as described above, the terminal block 16 is fixed to the trans axle 6, and the PCU 6 is attached to the trans axle 6 from above. At that time, the bus bar 26 passes through the opening 8H of the PCU 8. After the bus bar 26 has passed through the opening 8H, the bus bar 26 is fixed by the inverter 24 and the bolt 18d.
Although the electric vehicle drive unit 10 of the embodiment fixes the bus bar 26 and the terminal block 16, the technique disclosed in the present specification is not limited to this fixing method. A fixing method may be adopted in which the bus bar 26 is first fixed to the motor terminal 22a, and then the bus bar 26 is covered with the terminal block 16 from above.

Further, a service cover 20 is provided on the outside of the terminal block 16. As described above, the upper side of the service cover 20 is fixed to the PCU 8, and the lower side is fixed to the trans axle 6. An ECU 12, which is a peripheral device, is provided on the outer side of the terminal block 16. The method of mounting the ECU 12 on the vehicle is not shown or described here.

As described above, the bus bar 26 transmits three-phase alternating current from the inverter 24 to the motor terminal 22a. At this time, the bus bar 26 radiates high frequency electromagnetic noise. The electromagnetic noise propagates from between the PCU 8 provided with the terminal block 16 and the trans axle 6 to the ECU 12 which is a peripheral device. In the electric vehicle drive unit disclosed in the present specification, the service cover 20 is provided on the outside of the terminal block 16. As described above, the service cover 20 is connected to both the case of the PCU 8 and the case of the trans axle 6. Here, since the trans axle 6 is fixed to the body of the hybrid vehicle 2, it can be electrically regarded as a part of the body. As mentioned above, the service cover 20 has conductivity. Therefore, the service cover 20 electrically connects the case of the PCU 8 to the body.

Due to the noise generated by the bus bar 26, an induced current flows through the service cover 20 arranged outside the bus bar 26, and the induced current generates a magnetic field. The magnetic field in which the induced current is generated is in the opposite direction to the magnetic field caused by the fluctuating current flowing through the bus bar 26, and cancels the magnetic field caused by the fluctuating current passing through the bus bar 26. Since the magnitude of the magnetic field generated by the bus bar 26 is one of the factors that determine the magnitude of the inductance, the inductance of the bus bar 26 is suppressed by canceling (a part of) the magnetic field of the bus bar 26 by the service cover 20.

As described above, in the electric vehicle drive unit disclosed in the present specification, the service cover 20 is used to suppress the inductance of the bus bar 26. By suppressing the inductance due to the high frequency electromagnetic noise radiated by the bus bar 26, the high frequency electromagnetic noise generated by the bus bar 26 can be reduced. As a result, the electromagnetic noise radiated from the bus bar 26 is suppressed from propagating beyond the service cover 20, and electronic devices such as the ECU 12 that are easily affected by the electromagnetic noise can be protected from the electromagnetic noise.

FIG. 7 and FIG. 8 show the state of noise around the electric vehicle drive unit 10 of the embodiment. FIG. 7 shows a distribution map of electromagnetic noise seen from above the vehicle. FIG. 7 (1) shows a distribution map in a state where the service cover 20 is not arranged, and FIG. 7 (2) shows a distribution map in a state where the service cover 20 is arranged. Further, in FIG. 7, the electromagnetic noise in the range where the hatching is dark is strong, and the electromagnetic noise in the range where the hatching is light is weak. As shown in FIG. 7 (1), the electromagnetic noise radiated by the bus bar 26 becomes stronger in the vicinity of the bus bar 26. The electromagnetic noise radiated by the bus bar 26 spreads radially, and the electromagnetic noise becomes weaker as the distance from the bus bar 26 increases.

As shown in FIG. 7 (2), by arranging the service cover 20 on the outside of the vehicle of the bus bar 26, the distribution of electromagnetic noise changes. Specifically, the service cover 20 blocks the radiation of electromagnetic noise and weakens the spread. That is, the service cover 20 weakens the intensity of electromagnetic noise around the bus bar 26. That is, by arranging the service cover 20 on the outside of the vehicle of the bus bar 26, it is possible to suppress propagation beyond the service cover 20 and protect electronic devices such as the ECU 12 which are easily affected by electromagnetic noise from electromagnetic noise. can.

FIG. 8 shows the component direction of the magnetic field at each part seen from above the vehicle. The arrows in FIG. 8 indicate the direction of the magnetic field. As described above, the bus bar 26 transmits three-phase alternating current from the inverter 24 to the motor 22. FIG. 8 shows the direction of the magnetic field around the bus bar 26 when the current flows from the lower side to the upper side of the vehicle, that is, when the current flows from the back side of the paper surface to the front side of the paper surface of FIG. FIG. 8 (1) shows the direction of the magnetic field when the service cover 20 is not arranged, and FIG. 8 (2) shows the direction of the magnetic field when the service cover 20 is arranged.

As shown in FIG. 8 (1), when the service cover 20 is not arranged, a counterclockwise magnetic field is generated by the current flowing through the bus bar 26. When the service cover 20 is arranged, an induced current flows through the service cover 20 from the upper side to the lower side of the vehicle due to a counterclockwise magnetic field. This induced current creates a clockwise magnetic field around the service cover 20. That is, the magnetic field generated by the service cover 20 is in the opposite direction to the magnetic field caused by the fluctuating current flowing through the bus bar 26. As described above, the magnetic field generated by the induced current flowing through the service cover 20 cancels out the magnetic field caused by the fluctuating current passing through the bus bar 26. As described above, the inductance of the bus bar 26 is suppressed by canceling (a part of) the magnetic field of the bus bar 26, which is one of the factors that determine the magnitude of the inductance by the magnitude of the magnetic field generated by the bus bar 26.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of claims. The techniques described in the claims include various modifications and modifications of the specific examples exemplified above. The technical elements described herein or in the drawings exhibit their technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the techniques exemplified in the present specification or the drawings can achieve a plurality of purposes at the same time, and achieving one of the purposes itself has technical usefulness.

2: Hybrid vehicle 4: Front compartment 6: Trans-Askle 8: PCU
6H, 8H: Opening 10: Electric vehicle drive unit 12: ECU
14: Engine 16: Terminal block 16a, b: Packing 18a, 18b, 18c, 18d: Bolt 20: Service cover 22: Motor 22a: Motor terminal 24: Inverter 26: Bus bar

Claims (1)

It is an electric vehicle drive unit in which an intermediate member is interposed between the power control device and the vehicle drive device and a conductive shielding plate is provided.
The power control device is housed in a conductive first case having a first opening.
The vehicle drive device is housed in a conductive second case having a second opening facing the first opening .
The intermediate member is a non-conductive sealing member that airtightly seals the first opening and the second opening, and the non-conductive sealing member extending from the first opening to the second opening . It is provided with a conductive member that penetrates the inside of the seal member and passes through the first opening and the second opening.
An electric vehicle drive unit in which the conductive shielding plate is arranged on the outside of the non-conductive sealing member, and the conductive shielding plate is connected to both the first case and the second case.

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